Cellulose composition and process



Patented Feb. 8, 1927.

UNITED STATES WILLIAM G. LINDSAY, 0F NEWARK, NEW

JERSEY, ASSIGNOR TO THE CELLULOID COMPANY, A CORPORATION OF NEW JERSEY.

CELLULOSE COMPOSITION AND PROCESS.

Ho Drawing.

This invention relates to a process for rendering certain inflammable materials, substance, or compounds, non-inflammable, and to the reparation of commercially useful non-inflammable articles, such as paper, textile fabrics, cellulose plastics, pyroxylin plastics and the like. i

The degree of non-infiammability sought for is that which will not permit of a self sustaining combustion, after the application of a flame at ordinary or normal temperature. This degree of non-inflammability will however, be varied according to desired conditions.

rials which ermit of a self sustaining combustion by t e application of a flame at ordinary or normal temperature may be prevented from burning under ordinary conditions and rendered non-inflammable provided there is present in suitable combination a heat absorbing compound capable of absorbing or taking up through decomposition, volatilization, or other change, all or the major part of the heat that would be necessary to raise the material or its components to the point at which ignition could be sustained.

This heat absorbing, or endothermic, substance or compound should be of such nature that it will decompose or otherwise be in condition to absorb heat before or when the temperature of combustion of the material to be rendered non-inflammable has been reached. The absorption of heat will thus proceed at such a rate as to prevent the combustible material from attainin its temperature of ignition. 'Jhe endoiihermic substance or compound will also be selected having in view other characteristics besides its heat absorbin capacity on decomposition in that it may he desired to im art other properties to the resultant pro not. The relative proportions of the combustible substance, i.'e., the substance to be rendered non-inflammable, and endothermic or heat absorbing what to meet conditions of strength, plasticity, transparency, or other desirable chargeneral will be dependent upon the amount of decomposition, in heat unit equivalents, that can take place at or below the temperature at which combustion could be sutamed by the exothermic compound if the heat of combustion were not acteristics, but in I have discovered that inflammable matesubstance, will be varied some-- Application filed April 25. 1922. Serial No. 556,532.

absorbed at a greater rate than at which it could be liberated. The general rule is that a sufficient quantity of endothermic substance should be employed to absorb upon its decomposition a suificient amount of heat to prevent a sustained combustion of the said exothermic subtance.

In carrying out my invention, any one of a number of products may be the aim. Tile characteristics of these products may vary from that of a hard, nonmoldable, dense solid sheet material which may be used for cutting out various objects such as brush backs, mirror backs, knife handle, etc., to that of a thin, highly flexible product which may be used for the veneering of fabrics, paper and the like or which can be used in place of various textiles and other flexible materials. The flexible compound may also be used as a substitute for leather. It may also possess the necessary characteristics required in compounds that are to be molded such as molded boxes, molded handles, molded brushes, mirrors, etc.,

In carrying out the invention the procedure will vary according to the nature and physical properties of the material treated. The exothermic substance which I pro ose to use will benitrocellulose, acetylcellu ose, or some cellulosic ester, ether, derivative, or compound.

In the following examples I give such proportions as will be applicable to compounds containing nitrocellulose, as this is the most inflammable of the cellulose derivatives and any substance that may be incorporated with the nitrate for the purpose of reducing, limiting or preventing combustion will be effective with other compounds of cellulose, and as a matter of fact, with cellulose itself.

The permanent or nonvolatile solvents, generally referred to as the plastlcizmg agents and which are to be combined w th the pyroxylin or other cellulose derivative for the purpose of bringing about the neces- 100 sary conversion, etc. in the course of manufacture, should be of such nature that the point of ignition is relatively high. In my experiments I have foundthat the organic phosphates posses the necessary characteris- 105 tics of solubilit and at the same time possess the requisite temperature of ignition. The most satisfactory results are produced with the aromatic phosphates because of their relatively high stability and resistance to decomposition, and because they possess at the same time the necessary solvent or plasticizing effect on the nitrocellulose, as well as a relatively high ignition point.

To a mixture of nitrocellulose and an arcmatic hosphate, as for exam le, liquid tricresylp osphate, I add a sufficient amount of lithium phosphate to prevent the combined mixture from sustaining i nition upon the application and withdrawn. of a flame. An example of proportions for this purpose is 100 parts of pyroxylin, 75 parts of liquid tricresylpliosp ate, and 125 parts of lithium phosphate (Li PO,.H O.) Material of this composition, when manufactured according to the usual methods as obtain in the pyroxy-- lin lastic industry, will ossess hardness, toug ness and moldability in similar degree to the usual varieties of celluloid, manufactured in the form of ivory, opaque colors and the like.

In the manufacture of these non-inflammable compounds I proceed substantially as in the manufacture of ordinary pyroxylin plastic materials incorporating the lithium phosphate compound with the soaked or colloidized mass of pyroxylin and liquid tricresyl hosphate prior to final mastication on the ro ls. This incorporation may be effected in kneaders or the lithium phosphate compound may be directly added during the course of mastication on the rolls. The lithium phosphate compounds may also be incorworated with the pyroxvlin in the same operation in which the liquid tricresylphoshate is incorporated, the method for which 18 described in my U. S. Patent No. 1,233,374, granted July 17, 1917. H

In the choice of liquid volatile solvent I may select any one or a combination 0 a number of the common ordinary solvents, such as methyl alcohol, ethyl alcohol, acetic ether, acetone, amyl acetate, or the various commercial grades and mixtures of these com ounds as are ordinarily found upon the mar et.

In the manufacture of the flexible noninflammable compound having the properties of leather and the like, I proceed as in the example specified but instead of em loying 75 parts of liquid tricresylphosp ate, I increase the amount to 200 arts to 100 parts pyroxylin. Material of t is composition may be worked up according to the usual method for the manufacture of pyroxylin plastic compounds and produced 1n the form of sheets by shaving from a block, or it may be dissolved in a suitable proportion of solvent such as wool alcohol, acetone and the like and spread upon a suitable surface such as a textile fabric, leather and the like.

I claim:

1. A composition comprisin a homogeneous non-fi rous cellulosic derivative and a fire-retarding ingredient comprising lithium phosphate containing water of crystallization, said fire retarding ingredient being present in sufficient amount to render the composition non-inflammable.

2. A composition containing a cellulose ester, an aromatic phosphate and in close association therewith lithium phosphate in sufficient amount to render the composition non-inflammable. I

3. A composition containing a cellulose ester, an aromatic phosphate and in close association therewith lithium phosphate containing water of crystallization said lithium phosphate being present in sufficient amount to render the composition non-inflammable.

4. A composition containing a cellulose ester and sufficient fire-retarding agent comprising lithium hosphate to render the composition non-in ammable.

5. A homogeneous composition containing a cellulose ester and tricresylphosphate in admixture with lithium phosphate in sufficient amount to render the composition non-inflammable.

6. A composition containin plasticized pyroxylin and lithium phosp ate in Simicient amount to render the composition noninflammable.

7. A composition comprising plasticized pyroxylin and lithium phosphate containing water of crystallization, said lithium phosphate being present in sufficient amount to render the composition non-inflammable.

8. The process of making a non-inflammable material which consists in mixing a cellulose derivative with an aromatic phosphate in the presence of a solvent common to both and incorporating into the mixture lithium phosphate in sufficient amount to render the composition non-inflammable.

9. A composition containin yrox lin P P y i an aromatic phosphate, and lithium phosphate in sufficient amount to render the composition non-inflammable.

10. A composition containing pyroxylin, an aromatic phosphate and lithium phosphate containing water of crystallization said lithium phosphate being present in suflicient amount to render the composition noninflammable.

11. A homogeneous composition containing p roxylin, tricresylphosphate and lithium p osphate in sufiicient amount torender the composition non-inflammable.

12. The process of forming a. homogeneous composition of reduced inflammability which conslsts in mixing liquid tricresylphosphate and lithium phosphate with hydrous pyro lin said lithium phosphate being present i n sufficient amount to render the composition I non-inflammable.

13. The process which consists in mixing liquid tricresylphosphate and lithium phosphate with hydrous pyroxylin, and manipu-' lating the mixture in the presence of a voletile solvent, said lithium phosphate being present in suificient amount to render the composition non-inflammable.

14. A homogeneous tough non-inflammable cellulose derivative composition containing a. fire-retarding agentjn excess of 25 per cent of said com osition, said fire retarding agent comprising lithium phosphate.

15. A composition having substantially the physical properties of the usual lin plastics and comprising a combusti le orp roxy-.

g anic ingredient and a fire-retarding ingredlent, said latter ingredient consisting of lithium phosphate in suflicient amount to render the composition non-inflammable.

16. A toughfireproof cellulose derivative composition containing lithium phosphate in excess of 25 per cent of said composition. 17. A cellulose derivative composition having substantially the physicalv roperties of the usual pyroxylin plastics an containing in excess of 25 per cent of lithium phosphate.

WILLIAM G. LINDSAY.

Patent No. 1,616,91t

It is hereby mentioned patent requiring correction las follows:

a me Patent should be read with this correction the case in the Patent Oflice.

Signe and sealed this 15th day of March, A. D. 1927.

word posses read possess; page that the said Letters same ma conform to the record of [sun] ganic ingredient and a fire-retarding ingredient, said latter ingredient consisting of lithium phosphate in suflicient amount to render the composition non-inflammable.

16. A tough fireproof cellulose derivative composition containing lithium phosphate in excess of 25 per cent of said composition. 17 A cellulose derivative composition having substantially the physical roperties of the usual pyroxylin plastics an containing in excess of 25 per cent of lithium phosphate.

WILLIAM G. LINDSAY.

Jflcate of Correction.

Granted February 8, 1927, to

WILLIAM G. LINDSAY. certified that error appears in the rinted specification of the aboveage 1, line 105, for the missjielled 59. for the word wool read woo and therein that the M. J. MOORE, Acting Commissioner of Patents.

flute of Correction. Patent No. 1,616,910 Granfod February 8, 1927, to

WILLIAM G. LINDSAY.

It is hereby certified that error appoints in the E rinted specification of tho abovementioned patent requiring correction as follows: age 1,1me 105 for the 111188 elled word posses rea'd posaess; page 2, lino 59, for the word wool read woo an that the said Letters Patent should be read with this correction therein that the some ma. conform to the record of the case in the Patent Oflice.

Sign and sealed this 15th day of March, A. D. 1927.

M. J. MOORE,

Actmg Gomemmmwr of P 

